Well, yeah, it's all subjective - and actually quite tenuous - so you won't know good and bad until you actually make the call on it. Maybe you've had the experience even of coming around on some music you previously thought was bad.

Or like: one time I listened to a bunch of new music I had dug up and wasn't sure there was anything I liked. Two days later, I had a song in my head. Turned out to be one of the ones I had listened to. But I had to listen to everything all over again to find it! ദി(ㅠ﹏ㅠ) Glad I did - there were other gems in there.

Anyway, great quote.